Electric connector



HIDEO NAGANO Oct. 21, 1969 ELECTRIC CONNECTOR 8 Sheets-Sheet 1 Filed April 12, 1968 m ulgrl VIIIIIIIIIIIIIIIIIIIIA Oct. 21, 1969 HIDEO NAGANO 3,474,389

ELECTRIC CONNECTOR Filed A ril 12, 1968 8 heets-Sheet 2 Oct. 21, 1969 HIDEO NAGANO ELECTRIC CONNECTOR 8 Sheets-Sheet 5 Filed April 12, 1968 Fig.7

Oct. 21, 1969 H|DEO NAGANO 3,474,389

ELECTRIC CONNECTOR Filed April 12, 1968 8 Sheets-Sheet 4 Oct. 21, 1969 HIDEO NAGANO 3,474,389

ELECTRIC CONNECTOR Filed April 12, 1968 8 Sheefls-Sheet 5 Och 1969 HIDEO NAGANO ELECTRIC CONNECTOR 8 Sheets$heet R.

Filed April 12, 1968 Oct. 21, 1969 H1090 NAGANb 3,474,389

ELECTRIC CONNECTOR Filed April 12, 1968 8 Sheets-Sheet Oct. 21, 1969 HIDEO NAGANO 3,474,389

ELECTRIC CONNECTOR Filed April 12, 1968 8 Sheets-Sheet 8 United States Patent US. Cl. 339-95 17 Claims ABSTRACT OF THE DISCLOSURE An electric connector having an interconnecting conductor plate, two kinds of plate springs, and an actuating means. The plate springs are adapted to urge electric wire conductors to be connected against the interconnecting conductor plate so as to provide stable electric and mechanical connection of the wire conductors.

This invention relates to an electric connector, more particularly to a connector of electric wires, in which each conductor of the wires to be connected is urged to an interconnecting conductor plate by two kinds of plate springs, so as to provide stable electric and mechanical connection therebetween.

Terminal boards are widely used in various electric and electronic industries to interconnect electric conductor means of different kinds, such as single or bundled electric wires, singleor multi-core cables, single or stranded bare conductors, etc. A known terminal board for connecting electric wire conductors comprises one or more interconnecting conductor plates, each having a pair of fastening screws located at opposite ends thereof, and an insulating supporting means, such as a board made of electric insulating material, to hold the interconnecting conductor plates thereon with proper spacings between them. Each end of the wires to be connected is secured to the interconnecting conductor plate by means of the fastening screws. Such terminal boards are simple in construction and provides electric connection with a low contact resistance. However, they have the following disadvantages.

(1) To fasten each bare or insulation-stripped wire conductor to the terminal board, the end portion of each conductor has to be bent or wound around the fastening screw, so as to insure reliable engagement of the wire conductor with the fastening screw. Such bending or winding of the Wire conductor end portions amounts to considerable labor work.

(2) When terminal pieces are used at each end of the wire conductor, the mounting of such terminal pieces securely on the wire conductor also amounts to noticeable labor work.

(3) The fastening screws of such terminal board tend to be loosened when they are used under vibratory conditions, resulting in an increase in the contact resistance between the wire conductors connected thereby.

(4) When stranded conductors are used, the contact resistance tends to be unstable.

(5) Incomplete tightening of the fastening screws results in a high contact resistance.

(6) Due to the existence of exposed metallic portions, there is a danger of contamination and electric shock to man. Concealing the metallic portions with insulating members results in an increased cost and an increase in labor work for connecting and disconnecting operation of the wire conductors.

3,474,389 Patented Oct. 21, 1969 (7) Laborious check is necessary to keep low contact resistance between wire conductors connected thereby.

Therefore, an object of the present invention is to obviate such difficulties of known terminal boards by providing a novel electric connector, which can be operated with ease and provide sturdy mechanical connection as well as stable electric connection between wire conductors.

The electric connector, according to the present invention, is characterized by comprising a housing made of electric insulating material, a spring means including one or more stopping plate springs having both ends thereof turneclback by an angle larger than degrees and a clamping plate spring, an interconnecting conductor plate to receive wire conductors between said spring means and said interconnecting conductor plate, and an actuating means to actuate said spring means so as to urge said wire conductors to be connected against said interconnecting conductor plate at two or more points thereof by said spring means.

The reason for turning back the end portions of the stopping plate spring is as follows. If the wire conductors to be connected are urged against the interconnecting conductor plate at right angles, satisfactory electric characteristics of the connection can be achieved, but mechanical resistance against a force to pull the conductors out of the connector is produced only at right angles to such pulling force, or at the least effective angles. In other words, wire conductors can be readily pulled out of the connector unless they are urged by considerably large forces against the conductor plate. Each end of the stopping plate spring according to the present invention is turned back by an angle larger than 90 degrees, so that upon depression of the stopping plate spring, there is produced an elastic force having a component in the longitudinal direction of the conductors being connected, in the sense toward the inside of the connector. With such component force, the stopping plate spring engages the wire conductor in a Wedge-like fashion. As a result of it, the stopping plate spring exerts a large resistance against pulling of the wire conductor out of the connector. It was confirmed by experiments that the Wire conductors are securely joined to each other both electrically and mechanically through the interconnecting conductor plate by using a special spring means, which comprises one or more stopping plate springs having each longitudinal end portion turned back by an angle larger than 90 degrees and a clamping plate spring to urge the wire conductors to be connected against an interconnecting conductor plate at right angles.

Thus, with the electric connector according to the present invention, the wire conductors to be connected are urged against the interconnecting conductor plate by both the stopping and clamping plate springs, and hence, the wire conductors can be connected electrically and mechanically in a very stable manner. The wire conductors thus connected have a very high mechanical resistance against pulling out of the wire connectors, and their elec tric contact resistance is in the order of 10- ohm, which is the same as or less than that in the case of conventional fastening screw type connector. The use of the plate springs enables uniform and non-loosening connection of various kinds of wires, regardless of whether they are single conductors, bundled conductors, or stranded conductors. With the electric connector of the present invention, there is no danger to forget tightening the fastening screws, which can happen in the case of known terminal boards, and there is no need to provide any locking means for the fastening screws. The electric connector of the present invention is advantageously applied to vibratory devices, because it does not have any parts liable to loosening by vibration, and its electric contact resistance will not be changed by any vibration.

Furthermore, with the electric wire connector of the invention, the only preparation necessary for connecting wire conductors is to remove the insulation of the wire by a required length. There is no need to bend or wind the bare wire conductors around fastening screws, or to use compression type terminal pieces mounted to the conductor ends. Thus, the connecting process is greatly simplified, and the time for completing the connection is reduced to less than about /5 of that of known connectors.

A preferred embodiment of the present invention is characterized in that a cam lever having a downward projection is pivotally mounted on the housing of the connector to actuate the spring means, which cam lever movable between an actuated position to actuate the spring means by said downward projection so as to hold wire conductors as connected by urging them against the interconnecting conductor plate and a released position to remove the downward projection away from the spring means so as to allow free insertion and removal of the wire conductors into and out of the wire connector. With such preferred embodiment of the wire connector according to the present invention, wire conductors to be connected can be joined and separated simply by turning the cam lever to the actuated position and to the released position, respectively. The connector can be operated very quickly and easily. A very stable connection of wire conductors can be achieved regardless of whether the operator is experienced or not. In other words, the connection by the connector according to the present invention has a very high reproducibility. Moreover, there is no need for any additional tools, such as drivers, for making wire connection by the connector, because just removal of the insulation of the wire by a required length is sufiicient for the connection. Furthermore, all the electric conductive portions of the connector and the wire conductors being connected are completely concealed by the insulating housing of the connector, and hence, there is no danger of causing electric shock to man by contact with exposed conductive portions. Thus, protective cover for the connector is not necessary at all.

Another embodiment of the connector according to the present invention is characterized in that a vertically extending rotatable lock button is fitted in a cylindrical opening formed on the housing, and that a lock pin is secured to said lock button at the lower end threof, in such manner that the lock pin engages a cam surface formed at the lower edge of said cylindrical opening, so as to cause vertical reciprocation of the lock button in responses to rotation of the lock button around the vertical axis thereof. The cam surface, for instance, have one or more uppermost positions and corresponding number of lowermost positions, each provided with a groove to receive said lock pin. When the lock pin engages the cam surface of the cylindrical opening at the uppermost position, the spring means is released to allow free movement of the wire conductors to be connected in the connector. On the other hand, when the lock pin engages the lowermost position of the cam surface, the lock button actuates the spring means to urge the wire conductors to be connected against the interconnecting conductor plate, so as to cause stable mechanical and electric connection thereof. With such lock button, the connector can be mounted in a very limited space where the rotation of the cam lever of the preceding embodiment cannot be effected.

A ditferent embodiment of the connector according to the present invention is characterized in that the spring means comprises an elongated stopping plate spring, each end of which is turned back toward the interconnecting conductor plate by an angle larger than 90 degrees, so as to form bent-leg-like portions, and an elongated V-, W-, or wave-shaped clamping plate spring disposed between the stopping plate spring and the interconnecting conductor plate so as to clam wire conductors toward the interconnecting conductor plate at one or more points.

The end portions of the clamping plate spring extend towards the bent-leg-like portions of the stopping plate spring. The clamping plate spring is higher than the stopping plate springs when no external force is applied thereto. Upon depression of the spring means by a suitable actuating means, the longitudinal end portions of the clamping place spring engage the bent corners of the stopping plate spring, While the bent-leg-like bent portions of the stopping plate spring rotates around the bend corner in outward direction or away from the non-bent portion of the stopping plate spring.

With the spring means of the last-mentioned construction, after the longitudinal end portions of the clamping plate spring engage the bent corners of the stopping plate spring, the former is kept in contact with the latter until the spring means is released. According to the experiments carried out by the inventor, the thus engaged combination of the stopping and clamping plate springs provides a considerably increased mechanical strength, so as to urge the wire conductors against the interconnecting conductor plate with a force materially larger than that of the preceding embodiments. When the spring means is released, the stopping plate spring is raised upwards by means of the clamping plate spring, so that the tip of the bent-leg-like portions of the stopping plate spring is separated from the wire conductors to be connected to insure smooth pull out of the wire conductors without any interruption by such bent-leg-like portions. The outwards rotation of the bent-leg-like portions of the stopping plate spring upon actuation of the connector prevents excessive contraction of the clamping plate spring, to reduce the fatigue of such plate spring material and improve the durability thereof.

Another embodiment of the present invention is characterized in that the spring means includes a pair of stopping plate springs overlaid on a clamping spring. Each stopping plate spring has both ends turned back towards the clamp ing plate spring, and the end portions of the upper stopping plate spring are turned by an angle larger than the corresponding angle of bending the lower stopping plate spring. When a cam lever, or a lock button, is actuated, the end portions of the lower stopping plate springs extend outwards, so as to push the corresponding end portions of the upper stopping plate spring outwards. An auxiliary plate spring is disposed upon the upper stopping plate spring at the central portion thereof to supplement and equalize the depressing force. With such pair of stopping plate springs and an auxiliary plate spring, the force to urge the conductors against the interconnecting conductor plate is increased to provide a highly satisfactory electric and mechanical connection of wire conductors.

Another embodiment of the present invention is characterized in that end portions of a clamping plate spring extend outwardly in such manner that, upon depression of a cam lever or a lock button, such end portions of the clamping plate spring engage bent end portions of a stopping plate spring to increase the extent of outward movement of the bent end portions of the stopping plate spring. The increased outward movement of the bent end portions of stopping plate spring of this embodiment results in an increase of the urging force acting on the clamping plate spring towards an interconnecting conductor plate.

Another embodiment of the present invention is characterized by comprising a pair of mutually insulated connector assemblies mounted on a housing, each assembly has a spring means, an actuator of the spring means, and an interconnecting conductor plate; and a pair of terminals each connected to the interconnecting conductor plate of the corresponding connector assembly. With such pair of connector assemblies, each wire conductor to be connected can be inserted into or removed out of the connector, regardless of the conditions of the other wire conductor to be connected thereto. Moreover, the terminals can be connected to any outside circuit, such as a fuse, a

current limiting type or no-fuse type circuit breaker, an alarm device, or the like.

According to a feature of the present invention, a number of connectors, representing any of the aforesaid construction, can be assembled to form a connector assembly to facilitate interconnection of wires in an orderly and compact fashion. For such purpose, one or more of through holes are bored at certain locations of each connector, so that a connecting bolt penetrates through such through holes of the connectors to combine a desired number of connectors in an assembly. A rectangular spring nut is applied to either end of the connecting bolt protruding from the outermost one of the thus assembled connectors, so as to tighten the assembly. Thereafter, an end block is mounted on each end of the assembly, which end block has one or more rectangular recesses to receive the rectangular spring nut thus applied to each end of the connection bolt. The resilient engagement of the rectangular spring nut with the corresponding recess of the end block results in a snapping action to hold the end blocks as a part of the connector assembly thus assembled.

The connector assembly thus assembled does not have any conductor portion exposed to the outside. Thus, the danger of electric shock to man due to contact with live conductor portions is completely eliminated. Accordingly, there is no need at all to use a protective cover for concealing the exposed conductor portions. With such construction of the connector, any number of connectors can be assembled very easily and quickly.

In another preferred embodiment of the invention, to facilitate assembling thereof, one of the side walls to abut adjacent connector is dispensed with, and a trough-shaped interconnecting conductor plate is used. With such construction, the thickness of each connector, to be used as a component unit of the aforesaid connector assembly, is reduced, so that the total length of the connector assembly can be shortened. The trough-shape interconnecting conductor plate acts as a guide of wire conductors inserted in the individual connector, and such conductor plate also prevents the spring means from falling apart when each individual connector is removed from the assembly.

An advantage of the connector according to the present invention is in that wire conductors can be easily connected and disconnected simply by operating an actuating means, such as a cam lever or a lock button. However, such easiness of operation is liable to mischievous connection or disconnection of wire conductors. To prevent any mischievous operation, a lock lever, preferably an angle member, can be placed across the connector assembly while holding each end thereof by the end blocks, so that any connector cannot be operated unless the lock lever is removed.

Another embodiment of the present invention is characterized in that the surface of the interconnecting conductor plate is so processed as to produce better electric contact with wire conductors to be connected thereby. For instance, file-like cuts can be formed on the surface of the interconnecting conductor plate to insure better contact with the wire conductors by reducing the contact resistance between the conductor plate and the wire conductors being connected thereby.

For a better understanding of the invention, reference is made to the accompanying drawings, in which:

FIG. 1 is a plan view of a connector, according to the present invention, which uses a cam lever;

FIG. 2 is a sectional view taken along the line II-II of FIG. 1;

FIG. 3 is a sectional view taken along the line IIIIII of FIG. 2;

FIG. 4 is a top view of a connector using a lock button, according to the present invention;

FIG. 5 is a sectional view taken along the line V-V of FIG. 4;

FIG. 6 is a sectional view, taken along the line VI-VI of FIG. 5;

FIG. 7 is a vertical sectional View of a connector according to the present invention, in which a pair of lock buttons are used;

FIG. 8 is a schematic diagram of a spring means having a combination of plate springs, to be used in a connector according to the present invention, shown in the state as released;

FIG. 9 is a schematic diagram, showing the spring means of FIG. 8 in the state as depressed by a cam lever, shown with wire conductors inserted between the spring means and an interconnecting conductor plate;

FIG. 10 is a view similar to FIG. 9, showing a wave shaped clamping plate spring;

FIG. 11 is a view similar to FIG. 10, showing a V- shaped clamping plate spring;

FIG. 12 is a top plan view of a connector having a fuse incorporated therewith, according to the present invention;

FIG. 13 is a vertical sectional view taken along the line XIII-XIII of FIG. 12;

FIG. 14 is a side elevation of the connector of FIG. 12;

FIG. 15 is a diagrammatic illustration, showing the construction of a connector assembly, consisting of connectors according to the present invention;

FIGS. 16 and 17 are, respectively, a top plan view and a front elevation of an end block to be used at either end of the connector assembly of FIG. 15;

FIGS. 18 and 19 are, respectively, a front elevation and an end view of a connector usable in the connector assembly of FIG. 15;

FIG. 20 is a perspective view of the connector assemy;

FIGS. 21 and 22 are, respectively, a front elevation and an end view of a connector, according to the present invention, which is particularly suitable for connecting conductors having different diameters; and

FIGS. 23 and 24 are sectional views similar to FIG. 2, illustrating further modifications of the present invention, respectively.

Like parts are designated by like numerals and symbols throughout the drawings.

Referring to FIGS. 1 and 2, illustrating a connector embodying the present invention, which is generally depicted by a symbol U, a housing 1 of the connector is made of electric insulating material, such as synthetic resins, by a suitable shaping means on a mass production basis at a low cost. A bottom wall 2 of the housing 1 receives an interconnecting conductor plate 3, which is fastened to the bottom wall 2, preferably by embedding. Hollow space 4 within the casing 1 above the bottom wall 2 receives a spring means consisting of a stopping plate spring 5 and a clamping plate spring 6. Both ends of the stopping plate spring 5 are turned back inwardly by an angle larger than degrees. The clamping plate spring is disposed between the stopping plate spring 5 and the interconnecting conductor plate 3 and it is so shaped as to clamp securely conductors to be connected against the interconnecting conductor plate 3. In this particular embodiment, the clamping plate 6 has a central portion bent downwards to make contact with wire conductors 9, 10 to be connected, while both ends once extend upwards to engage the bent portions of the stopping plate spring 5, and then they are bent downwards again to make contact with the wire conductors 9, 10. The configuration and number of stopping and clamping plate springs are not limited to those as illustrated in the figures, and there can be many other effective shapes and combinations, as will be disclosed hereinafter.

In this embodiment, as shown in FIGS. 1 to 3, a cam lever 7 is pivotally supported by the housing 1 through a shaft 8 journalled by the housing. When the cam lever 7 is at its actuated position, as best shown in FIG. 2, the lower end of the cam portion of the lever 7 engages the central portion of the stopping plate spring so as to urge the latter downwards. Thus, the tip portions of the stopping plate spring 5 urge the wire conductors 9 and 10, to be connected each other, against the interconnecting conductor plate 3 at points A and E, respectively. The elevated end portions of the clamping plate spring 6 are also forced downwards by the cam lever 7 through the stopping plate spring 5, so that the clamping plate spring urges the conductors 9 and 10 against the interconnecting conductor plate 3 at three points B, C, and D.

As a first step to connect wire conductors 9 and 10 by the connector U, according to the present invention, the cam lever 7 is turned counterclockwise around the axis 8, so as to allow insertion of the wire conductors 9 and 10 thereto. Then the lower end portion of the cam lever is moved away from the stopping plate spring 5, and the stopping plate spring 5 and the clamping plate spring 6 are released. Thus, the wire conductors 9 and 10 can be inserted without any substantial friction between the interconnecting conductor plate 3 and the spring means through conductor holes 11 and 12 bored through the housing 1. If insulated wires are to be connected, such insulation should be removed by a predetermined length from the end thereof, so that only the bare conductors of such wires engage both the spring means 5, 6 and the interconnecting conductor plate 3. By inserting tip portion of the thus cut insulation into the connector U, one can insure that no bare conductor portions, or lively charged conductor portions, are exposed to the outside, so that the danger of electric shock due to direct contact with live conductors can be completely eliminated.

As the wire conductors are inserted in the connector U, the plate springs can be easily moved upwards by the conductors, depending on the thickness of the wire conductors.

Then, the cam lever 7 is turned clockwise, so that the lower end of the cam portion of the lever 7 depresses the stopping spring 5 at the central portion thereof, so as to cause engagement of the end portions of the plate springs and the conductors at points A and E. Thus, the conductors 9 and 10 are urged against the common interconnecting conductor plate 3, to electrically connect them together. Due to the fact that both ends of the stopping plate spring 5 are turned back by an angle greater than 90 degrees, upon depression of the spring plate 5 vertically downwards, there are produced horizontal components of force in the sense to keep the conductors 9 and 10 toward the center of the connector U. Besides, the tips of the plate spring 5 slightly bite the wire conductors 9 and 10 to be connected, to stop the wire conductors securely against pulling out of the connector U. Therefore, the stopping plate spring 5 not only stops the wire conductors securely, but also urges wire conductors against the interconnecting conductor plate 3, to fulfill the clamping action, even though it is not called as a clamping spring. One may call the plate spring 5 as a stopping-clamping plate spring.

At the same time, the clamping plate spring 6 is also depressed downwards by the cam lever 7 through the stopping plate spring 5. In this embodiment, since each wire conductor 9 or 10 is inserted into the connector U beyond the center thereof, as shown in FIG. 3, the clamping spring 6 urges the wire conductor 9 at two points B and C and the wire conductor 10 at two points C and D, against the interconnecting conductor plate 3. It is apparent that the clamping plate spring 6 not only clamps the wire conductors 9 and 10 by urging them against the conductor plate 3, but also fulfills the function of stopping the wire conductors from being pulled out of the connector U. Thus, one may call the plate spring 6 as a clamping-stopping plate spring, too.

Thus, in the connector U according to the present invention, use is made of spring means comprising a stopping plate spring 5 having both ends turned back by an angle larger than 90 degrees and a clamping plate spring 6 disposed underneath the stopping plate spring 5, so that wire conductors 9, 10 are electrically connected effectively by depressing the wire conductors against a a conductor plate 3 by the spring means, while insuring firm mechanical connection thereof against pull-out by the inwardly oriented engagement between the stopping plate spring and the wire conductors being connected.

In the particular embodiment, as illustrated in FIGS. 1 to 3, the spring means further comprises an auxiliary plate spring 13, which intensifies the pressure to urge the wire conductors 9, 10 against the conductor plate 3 of the connector, and at the same time pressure at both ends of the spring means 5, 6 is equalized by the auxiliary plate spring 13. Thus, the pressures at the points A and B become substantially the same as those at the points D and E, respectively.

Referring to FIG. 2, according to the present invention, it is possible to roughen the upper surface of the interconnecting conductor plate 3, so as to insure firm contact between the wire conductors 9 and 10 to be connected and the interconnecting conductor plate 3. For instance, ridges having a triangular cross-section can be formed on the conductor plate 3 at right angles with the wire conductors to be connected. Thereby, electric contact resistance between the wire conductors 9 and 10, which are connected through the thus roughened conductor plate 3, is considerably reduced, while increasing the frictional resistance against a force to pull-out the wire conductors 9 and 10 out of the connector U.

However, for most applications, satisfactory electric contact resistance and mechanical friction can be achieved without roughening the surface of the interconnecting conductor plate 3.

In this embodiment, the wire conductors 9 and 10 to be connected are inserted to the connector U from the opposite ends thereof, but the present invention is not limited to such arrangement alone. For instance, two wire conductors, such as a pair of parallel bare conductors, can be inserted into the connector U from one side thereof. In this case, it is preferable to connect two conductors of substantially the same size, to insure uniform and secure contact therebetween. If the wires to be connected are of different sizes, it is preferable to twist them together prior to inserting them into the connector.

FIGS. 21 and 22 show another embodiment, which is particularly suitable for inserting wire conductors of two different sizes from either side thereof. As best shown in FIG. 22, either side of the connector has a pair of inlet openings. The end portion of a stopping plate spring 5 is bifurcated, as depicted by 5a and 5b. A pair of clamping plate springs 6 is disposed underneath the stopping plate spring 5, so that each clamping plate spring can cooperate with the thus bifurcated end portion 5a or 5b of the stopping plate spring, respectively. A partitioning wall or separator S is inserted between the separate clamping plate springs 6. With such construction, wire conductors of different sizes, such as 10a, 10b, can be securely connected by the connector. If the diameter of the wire conductors to be inserted from One side of the connector are greatly different, it is necessary to provide a pair of separate stopping plate springs 5, instead of one stopping plate spring having bifurcated end portions, so that two independent spring means, each having a stopping plate spring and a clamping plate spring, can connect two such wire conductors by urging them separately to a common interconnecting conductor plate 3.

Referring to FIG. 2, when the cam lever 7 is turned counter-clockwise to its released position, the clamping plate spring 6 pushes the stopping plate spring 5 upwards at both ends thereof. Thus, the stopping plate spring 5 does not present any resistance against the removal of the conductors 9 and 10, as long as the cam lever is at its released position. When the cam lever is at its actuated position, the lower end of the cam portion, which depresses the central portion of the stopping plate spring 5, is positioned to the left of a vertical plane passing through the axis of the shaft 8. In other words, the vertical force applied to the cam lever 7 by the spring means 5, 6 produces a moment to rotate the cam lever 7 clockwise to lock the lever at the actuated position. Accordingly, once the cam lever 7 is turned clockwise to its actuated position, the cam lever is retained at the actuated position by the elastic force of the spring means, and the danger of loosening of the connector, such as the one due to vibration, is eliminated completely. In addition, the tips of the stopping plate spring slightly bite the conductors being connected, so as to produce very strong metallic bond between the edge of the plate spring 5 and edge of the conductors 9, to be joined thereby. Thus, electric contact resistance is reduced, to result in excellent electric properties of the connector.

For safety, all the conductor portions being joined by the connector are covered with suitable insulating material, such as housing 1. In order to facilitate circuit tests related to the connector U, a pair of through holes 38 are formed on the casing 1 to allow insertion of test bars therethrough for test purposes, as indicated by dotted lines in FIG. 2.

FIGS. 4 to 6 show another embodiment of the present invention, which has a lock button 14, instead of the cam lever 7 of the preceding example, to actuate the spring means 5, 6. In this embodiment, a cylinder portion depends from the top wall of a housing 1, as an integral part thereof. The lock button 14 is rotatably fitted in the cylinder 15, and a pin 16 is secured to the lower end of the lock button 14. The pin 16 engages a suitable cam surface formed at the lower portion of the cylinder 15, so as to depress and release the central portion of a stopping spring plate 5 as the lock button 14 is rotated around its axis.

For instance, a pair of inclined cam surfaces 17 are formed on the lower end surface of the cylinder 15, in such manner that each cam surface gradually extends downwards from one of the two uppermost positions, located at diagonally opposite positions of the bottom surface of the cylinder portion 15, toward one of the lowermost positions, located at the middle points of the two uppermost positions along the circular bottom surface, and then gradually extends upwards to the other one of the uppermost positions. A pair of grooves 18 are formed at the lowermost positions of the cam surface at the bottom of the cylinder portion 15, as shown in FIG. 6. When the lock button 14 rotates around its axis, the engagement of the pin 16 and the cam surface 17 forces the lock button 14 to move vertically, in conjunction with the elastic force of the plate springs 5 and 6.

FIG. 5 shows the lock button 14 in the state as engaged to the uppermost position of the cam surface 17 to release the plate springs 5 and 6. As the lock button 14 rotates from this position, the pin 16 moves down along the cam surface 17, until it fits in the groove 18. Accordingly, the lock pin 14 reciprocates the uppermost and the lowermost positions thereof. When the lock button 14 is kept at the lowermost position with the pin 16 fitted in the groove 18, the lower end of the lock button 14 depresses the central portion of the stopping plate spring 5, as well as the clamping plate spring 6. Thus, wire conductors 9 and 10 to be connected are urged against an interconnecting conductor plate 3.

When the W-shaped clamping plate spring 6 is depressed downwards, its end portions moves horizontally until they engage the bent end portions of the stopping plate spring 5, so that the former plate spring tends to extend the latter. With the plate springs 5 and 6 thus engaged each other, the spring means becomes strong to make its deformation diflicult. Thus, the force to urge the wire conductors 9 and 10 against the conductor plate 3 is intensified. The special intensifying effect of such combination of the stopping and clamping plate springs will now be described in further detail.

FIG. 7 illustrates another embodiment of the present invention, in which a pair of lock buttons are used. The lock buttons 14 used in this embodiment have essentially the same structure as the corresponding lock button 14, as described hereinbefore referring to FIGS. 4 to 6. Accordingly, no detailed explanation of the lock button 14 will be repeated hereinafter. Two elliptic clamping plate springs 6 are disposed between the stopping plate spring 5 and an interconnecting conductor plate 6. In addition, an equalizing auxiliary plate spring 13 is inserted between the lock buttons 14 and the stopping plate spring 5.

In such connector, if the two lock buttons are depressed, the equalizing auxiliary plate 13 is depressed at two corresponding points, to force the stopping plate spring 5 and the clamping plate springs 6 downwards. Thereby, a wire conductor 9 is stopped at a point A and clamped at a point C by the stopping plate spring 5, and moreover, the wire conductor 9 is depressed at another point B by one of the elliptic clamping plate springs 6. Similarly, another wire conductor 10 to be connected is stopped at a point E and clamped at point C by the stopping plate spring 5, While additionally clamped at another point D by the other one of the elliptic clamping plate spring 6. By using two lock buttons associated with two clamping plate springs, the depressive force acting on each wire conductor 9 or 10 can be controlled independently, without affecting to another force acting on the other wire conductor 10 or 9. More particularly, this embodiment has an advantage in that a wire conductor 9 or 10 can be inserted into and removed from the connector, while retaining the other wire conductor 10 or 9 as clamped, by operating one of the lock buttons 14 selectively.

In the embodiment depicted in FIG. 7, a pair of lock buttons are used. It is of course possible to design similar comiector by using two cam levers, as designated by the numeral 7 in FIGS. 1 and 2, or any other suitable means to actuate the spring means 5, 6.

FIGS. 8 to 11 illustrate three different assemblies of stopping and clamping springs, usable'in the connector according to the present invention. The examples are characterized in comprising a pair of such stopping plate springs 51, 52, a clamping plate spring 6, and an auxiliary plate spring 13, in which the stopping plate springs are so related with the clamping plate spring that the depressing force generated thereby is considerably greater than the total sum of the individual depressions of the stopping and clamping plate springs.

An embodiment, as depicted in FIGS. 8 and 9 comprises two stopping plate springs 51 and 52, each having both end portions turned back toward the center of the connector, a W-shaped clamping plate spring 6 having end portions extending toward the turned back portions of the stopping plate springs 51 and 52, and a pressure equalizing auxiliary plate spring 13 disposed on the central portion of the stopping plate springs. FIG. 8 shows the spring means in the state as placed on an interconnecting conductor plate 3 without applying any depressive force thereto.

In FIG. 8, an angle 0 between the interconnecting conductor plate 3 and the turned back portion of the upper stopping plate spring 51 is larger than another angle 6 between the conductor plate 3 and the turned back portion of the lower stopping plate spring 52. The vertical height of the turned back portion of the upper stopping plate spring 51 is substantially the same as the corresponding height of the plate spring 52. The W- shaped clamping plate spring 6 has an inversed V-shaped central portion with a top angle 0 as well as two V- shaped side portion each with a top angle 0 The vertical height of the end portions of the clamping plate spring 6 is selected to be higher than that of the stopping plate springs 51 and 52 by h. In other words, when the spring means is not depressed, there is a height difference It between the stopping plate springs 51, 52 and the clamping plate spring 6. With such height difference, the danger of interference against withdrawal of wire conductors due to the turned back portions of the stopping plate springs is completely eliminated to insure easy withdrawal thereof.

FIG. 9 shows the spring means of FIG. 8, in the state as actuated by inserting wire conductors 9 and 10 between the spring means and the interconnecting conductor plate and depressing the central portion of the auxiliary plate spring 13 by a cam lever 7.

As the depression by the cam lever 7 increases, the clamping plate spring 6 is depressed in such manner that the angle increases, while the other angle 0 decreases. Thereby, the overall height of the clamping plate spring is lowered, and at the same time, both ends of the clamping plate spring 6 slide horizontally along the lower surface of the lower stopping plate spring 52 towards the bent corner of the latter, until the opposite tips of the clamping plate spring 6 strike the corresponding bent corners of the stopping plate spring 52, so that any further lowered, to surging outwards the turned back Then each tip of the clamping plate spring 6 becomes fulcrums, which support the bent portions of the stopping plate springs 51 and 52. Thus, that portion of the spring means which includes the tips of the clamping plate spring 6 in contact with the bent portion of the stopping plate spring 52 and the central portion of the stopping plate springs 51, 52 becomes very sturdy, and it becomes very difficult to deform such portion of the spring means.

If the cam lever 7 is moved further downwards, the central portion of the stopping plate springs 51, 52 is further lowered, to surging outwards the turned back portions of the stopping plate springs around the aforesaid fulcrums, respectively. Thus, the angles 0 and 0 increase so as to urge conductors 9 and 10 against the interconnecting conductor plate 3 with an increased pressure. At the same time, depressing points, or the lowermost points, of the clamping plate spring 6 are also forced downwarjds with increased depression to tightly urge the conductors 9 and 10 against the interconnecting conductor plate 3. In this process, as the angles 0 and 0 increase, the vertical component of the force to swing the turned back portions of the plate springs 51, 52 becomes larger to intensify the force urging the conductors 9 and 10 against the conductor plate 3. It should be noted here that the tip of such turned back portions of the stopping plate springs 51, 52 slightly bite the conductors, so that there are produced considerably large resistance against withdrawal of the conductors.

With such arrangement of the spring means, the degree of swing of the ,turned back portions of the stopping plate springs 51, 52 is limited, and hence, the durability of these plate springs is improved. It is apparent from the foregoing that the stopping plate springs 51 and 52 prevent withdrawal of the conductors 9 and 10 satisfactorily, even when the force urging the wire conductors against the conductor plate is not so large.

In order to increase the number of points to urge the wire conductors 9, 10 down to the interconnecting conductor plate 3, it is permissible to use a wave-shaped, or corrugated, clamping plate spring 6, as shown in FIG. 9. In this particular embodiment, the longitudinal end portions of the clamping plate spring 6 are rolled back to the outside thereof. Upon application of depression from above by a cam lever 7, the thus rolled back end portions of the clamping plate spring moves outwards while sliding the lower surface of a stopping plate spring 52, in the same manner as the preceding W-shaped clamping plate spring. The rolled back portion of this clamping plate spring acts to swing more the turned back portions of the stopping plate springs 51, 52 than the preceding W-shaped clamping plate spring. Accordingly, the force to clamp conductors 9 and 10 against an interconnecting conductor plate is also intensified.

FIG. 11 illustrates a V-shaped clamping plate spring 6, having both ends rolled back in the same manner as the preceding corrugated clamping plate spring. The function and effects of this V-shaped clamping plate spring are substantially identical with those of the preceding clamping plate springs. The advantage of this V- shaped clamping plate spring is in its simplicity.

FIGS. 12, 13, and 14 show another embodiment of the present invention, which includes a pair of spring means to be actuated by separate cam levers, as well as a pair of separate interconnecting conductor plates to receive wire conductors to be connected. In other words, this embodiment includes a pair of connectors similar to the one as shown in FIG. 1, which are combined together in one housing. Rotatable cam levers 71 and 72 selectively actuate corresponding spring means, each comprising a stopping plate spring 51 (52) and a clamping spring 61 (62), respectively. An interconnecting conductor plate 31 is embedded in the bottom wall 2 of the housing 1 so as to receive a wire conductor 9 which is urged thereon by the spring means 51, 61 upon actuation of the cam lever 71. A separate conductor plate 32 is embedded in the bottom wall 2 to receive another wire conductor 10, which is to be connected with the wire conductor 9, when the wire conductor 10 is urged thereto by the spring means 52, 62 upon actuation of the cam lever 72. The interconnecting conductors 31 and 32 are electrically insulated to each other. In this particular embodiment, a pair of fuse holders 20 and 21 are connected to the interconnecting conductor plates 31 and 32, respectively, by a suitable means, such as screws. By inserting a fuse 22 across the fuse holders 20, 21, the conductor plates 31 and 32 are electrically connected together. With such construction, the Wire conductors 9 and 10 can be independently inserted to and removed from the connector, by actuating either of the cam levers 71 and 72.

In order to facilitate assembling a plurality of such connectors to form a connector assembly, shafts 81 and 82, which also act as indexing bosses, are formed on the opposite side walls of the housing 1, and recesses 81a and 82a are bored on the housing 1, so as to receive corresponding bosses of the adjacent connectors. Thus, each connector can easily register with each other by the engagement of the boss with the corresponding recess formed on the housing.

The outside means to connect the interconnecting conductor plates 31 and 32 is not restricted to fuse alone, but many other suitable means can be used therefor, e.g. a neon tube, a fuse with a lamp, a fuse with an indicator, a fuse with an alarm contact, etc. Furthermore, it is possible to mount receptacles on the interconnecting conductor plates 31 and 32, instead of the fuse holders 20 and 21, so that a current limiting circuit breaker, or any other connecting or testing means, can be plugged in the receptacles.

A salient feature of the present invention is in that any number of such connectors can be assembled together to form a connector assembly. Referring to FIG. 15 a suitable number of connectors U, such as 10, 20, or 30 connectors, can be easily assembled, and the thus assembled connectors are fastened together by mounting end blocks 23 at either end thereof. Each end block 23 has four square recesses 25 bored at four corners of one side thereof, as best shown in FIGS. 16 and 17. A circular recess 24 to receive one end of the shaft 8 of the cam lever 7, and a pair of elongated recesses 26, 27, to receive a card board 35 (to be described hereinafter) and a pro tective plate (to be described hereinafter), are bored on the upper end of the same side of the end block 23 as the recesses 25. On that side of the end block 23 which is opposite to the recesses 25, there are formed a shallow groove 29 at the lower end thereof and a deep groove 28 extending between the shallow groove 29 and the upper end thereof. The connector assembly can be mounted on any structural members by using a screw to be engaged on the shoulder portion of the shallow groove 29.

As shown in FIG. 15, an elongated shaft 8 is used in common for all the cam levers 7 of the connectors U in the assembly, and each end of the shaft 8 projects slightly out of the extreme outside connector U so as to fit in the circular recess 24 of the end block 23. A pair of bolts 33 penetrate through all the connectors in the assembly, and rectangular spring nuts 34 are threadedly applied to each end of the bolt 33 to tightly bind, the thus assembled connectors U. The rectangular spring nuts are elastically fitted in the square recesses 25 formed in the terminal blocks 23. Accordingly, a pluralityof connectors U can be easily and tightly assembled by the bolts 33 and the spring nuts 34, and also the end blocks 23 can be easily and securely mounted on either end of the connector assembly.

FIG. 20 shows a perspective view of a connector assembly t-hus assembled. A card board mark plate 35 can be fitted in the elongated rectangular recesses 26 on the end blocks 23, so that suitable marks and symbols can be inscribed on the mark plate to identify each connector U in the assembly.

FIGS. 18 and 19 shows another embodiment of the connector according to the present invention, which is particularly suitable for assembling, as shown in FIG. 20. This embodiment is essentially similar to the first embodiment, as described in detail hereinbefore referring to FIGS. 1 to 3. In this embodiment, the thickness of the connector is reduced by eliminating one side wall of a housing 1. A spring means comprises two stopping plate springs 51, 52, a W-shaped clamping plate spring 6 and an auxiliary plate spring 13. Wire conductors can be urged against an interconnecting conductor plate 3 in the same manner as any of the preceding embodiments. The interconnecting conductor plate 3 of this embodiment is of trough-like shape and placed on the bottom wall of the housing 1, so that a vertical edges of the trough-like conductor plate 3 is brought into contact with the side wall of the housing of an adjacent connector.

When individual connectors U are separated from the connector assembly, the trough-shaped conductor plate acts to retain the spring means in the housing 1 by preventing them from slipping out of the housing 1 and falling apart. The vertically bent side edges of the troughshaped conductor plate also act as guide members for leading the wire conductors inserted thereto for joining.

In order to penetrate a pair of bolts 33 (FIG. through all the connectors in an assembly, a pair of through holes 36 are bored at diagonally opposite corners of the housing 1. A groove 37 is formed on the upper surface of the housing 1 to receive a mark plate 35 therein. Each end of the mark plate 35 is fitted in the corresponding recess 26 in the end block 23. A test hole 38 is provided to facilitate circuit tests without disassembling the connector. It should be noted here that this embodiment does not have any metallic elements exposed to the outside, so that there is no danger of causing electric shock to man due to contact with live exposed conductors.

In order to prevent mis-operation of the cam lever of the connectors in the assembly, either intentionally or unintentionally, a protective or inhibition cross bar can be disposed above the cam levers 7 of the connectors in the assembly by fitting either end thereof in the corresponding elongated recess 27 on the end block 23. Thereby, no cam lever can be actuated, unless such protective cross bar is removed from the assembly. It is preferable to use an angle member for suchprotective cross bar to insure sufficient mechanical strength.

The present invention has been described by referring to several embodiments, but the invention is not restricted to such embodiments only. For instance, addi- 14 tional pins 101 and 102 can be formed integrally on the housing 1, as shown in FIG. 23. Thereby, the bent end portion of the stopping plate spring 5 can be loosely suppoted by such pins to ensure the most effective stopping action, as described herein'before referring to FIGS. 8 and 9. Moreover, the stopping plate spring 5 can be made of three portions; namely, two end portions consisting of relatively soft bent members, and a central portion consisting of a pair of relatively hard fiat plate springs, which flat plate springs sandwich edges of the bent end members, as shown in FIG. 24.

Thus, it is apparent that a number of different modifications in the structure and arrangement of parts can be made without departing from the scope and spirit of the invention.

What is claimed is:

1. An electric wire connector, comprising a housing made of electric insulating material; a spring means disposed inside of said housing and consisting of a stopping plate spring having both ends thereof turned back by an angle larger than degrees, and a clamping plate spring disclosed underneath the stopping plate spring; an interconnecting conductor plate means disposed on the upper surface of a bottom wall of the housing; and an operating knob rotatably supported at the top of said housing so as to selectively assume a first position to allow insertion of wire conductors to be connected between said spring means and said interconnecting conductor plate means, and a second position to depress said spring means so as to stop and clamp said wire conductors against said interconnecting conductor plate means by both said stopping and clamping plate springs.

2. An electric wire connector according to claim 1, wherein said operating knob is a cam lever pivotally supported by said housing, which cam lever has a cam surface adapted to depress said spring means, when the cam lever is at said second position thereof, and to release said spring means, when the cam lever is at said first position thereof.

3. An electric wire connector according to claim 1, wherein said operating knob is a vertical lock button fitted in a cylinder integrally formed on said housing, said lock button being rotatable around the vertical axis thereof and having a lock pin radially secured at the lower end thereof, said cylinder having at least an upper groove and at least a lower groove located radially along the bottom edge of the cylinder with a certain angular spacing therebetween, thereby said lock button assumes said first position at an angular position where said lock pin fits in said upper groove, and assumes said second position at another angular position where said lock pin fits in said lower groove.

4. An electric wire connector according to claim 1, wherein, said clamping plate spring has at least a longitudinal intermediate portion bent downwards and longitudinal end portions extending upwards towards the corresponding bent end portions of the stopping plate spring, the vertical distance between an uppermost part and a lowermost part of said clamping plate spring being larger than the corresponding vertical distance between an uppermost part and a lowermost part of said stopping plate spring when said operating knob is at said first position; whereas upon actuation of said operating knob to said second position, said clamping plate spring is depressed by said operating knob through said stopping plate spring so as to urge said conductors against said interconnecting conductor plate means at least at said intermediate portions, and simultaneously, both longitudinal ends of the clamping plate spring come into contact with said corresponding bent end portions of said stopping plate spring so as to force the tip portions of the stopping plate spring to urge said wire conductors against said interconnecting conductor plate.

5. An electric wire connector according to claim 4, wherein said clamping plate spring is Wshaped.

6. An electric wire connector according to claim 4, wherein said clamping plate spring is V-shaped.

7. An electric wire connector according to claim 4, wherein said clamping plate spring is corrugated.

8. An electric wire connector according to claim 4, wherein said stopping plate spring consists of an upper stopping plate spring element having both ends turned back by an angle larger than 90 degrees, a lower stopping plate spring element fitted underneath said upper plate spring element and having both ends turned back by another angle larger than said angle of the upper element, and an auxiliary plate spring element disposed on the upper plate spring element.

9. An electric wire connector according to claim 4, wherein said end portions of said clamping plate spring have each tip folded back, so that said end portions of the clamping plate spring intensifies the force of said bent end portions of said stopping plate spring to urge said wire conductors against said interconnecting conductor plate means.

10. An electric wire connector according to claim 1, wherein said interconnecting conductor plate has a filelike surface.

11. An electric wire connector according to claim 1, wherein said turned back end portions of the stopping plate spring are bifurcated.

12. An electric wire connector according to claim 1, wherein said housing has a pair of pin shafts integrally formed therewith so as to engage each said turned back end portion of said stopping plate spring.

13. An electric wire connector according to claim 12, wherein said stopping plate spring consists of a pair of separate bent end elements and a pair of fiat intermediate plate spring elements sandwiching edges of said bent end elements.

14. An electric wire connector, comprising a housing made of electric insulating material, a pair of mutually insulated spring means, each disposed inside of said housing and consisting of a stopping plate spring having both ends thereof turned back by an angle larger than 90 degrees and a clamping plate spring disposed underneath the stopping plate spring; a pair of mutually insulated conductor plates disposed on the upper surface of a bottom wall of the housing, each cooperating with said spring means, respectively; a pair of metallic terminals extending each from a said conductor plate to the outside of said housing; and a pair of operating knobs, cooperating with said spring means, respectively, each being rotatably supported at the top of said housing so as to selectively assume a first position to allow insertion of a wire conductor between said spring means and said conductor plate cooperating therewith, and a second position to depress said spring means so as to stop and clamp said wire conductor against said conductor plate by both said stopping and clamping plate springs.

15. An electric connector assembly, comprising a plurality of connectors, each consisting of a housing made of electric insulating material and having at least a bolt hole, a spring means disposed inside of said housing and having a stopping plate spring with both ends thereof turned back by an angle larger than degrees and a clamping plate spring disposed below said stopping plate spring, an interconnecting conductor plate disposed on the upper surface of a bottom wall of the housing, and an operating knob rotatably supported at the top of said housing so as to selectively assume a first position to allow insertion of wire conductors to be connected between said spring means and said interconnecting conductor plate and a second position to depress said spring means so as to stop and clamp said wire conductors against said interconnecting conductor plate by both said stopping and clamping plate springs, at least a connecting bolt penetrating through said bolt hole of each connector assembled; rectangular spring nuts mounted on each end of said bolt so as to fasten the assembled connectors, two end blocks each having at least a rectangular recess to resiliently fit said rectangular spring nut respectively.

16. An electric connector assembly according to claim 15, wherein said operating knob is a cam lever axially mounted on said housing, which housing lacks one side wall, and said interconnecting conductor plate is of trough-like shape.

17. An electric connector assembly according to claim 16, wherein each said end block has a rectangular groove at the top thereof, and an inhibition cross bar is extended across the assembly above the operating knobs and either end of the inhibition bar is fitted in and secured to said rectangular groove of the end block.

References Cited UNITED STATES PATENTS 2,623,087 12/1952 Latta 339198 2,644,144 6/1953 Richardson '339274 X 3,138,421 6/1964 Locher et a1 339- 3,152,851 10/1964 McLaughlin 33995 RICHARD E. MOORE, Primary Examiner US. Cl. X.R. 

